David Boyer discusses Node.js and Express at a conference, highlighting its capabilities for building web applications and the advantages of its asynchronous nature. The talk covers basic usage, the event loop, and how to manage modules using npm, along with tips to avoid callback hell. Boyer also introduces Express as a flexible web framework for Node.js, emphasizing its robust routing and middleware features.

1. All aboard the
Node.JS
Express
#SotR14

2. You know Node?
Kev McCabe is covering TDD
SotR14 - Mura Room

3. Who is this guy?
David Boyer
Senior Software
Developer
NHS Wales Informatics
Service

4. ...and yes... that's
me in the mask @
SotR13

5. Node.js
A JavaScript runtime
http://nodejs.org

6. The Details
JavaScript
Google's V8 engine
Open Source - MIT License
Cross platform
Single threaded code
Multi threaded IO

7. What can it do?
Build web applications
Creating command line tools
Create desktop applications
(node-webkit)

8. Who is using it?
PayPal, LinkedIn, Yahoo, Microsoft,
eBay, 37signals, LearnBoost,
Yammer, Walmart

9. Node in detail

10. In the beginning...
Install
Command line

11. Action!*
node
console.log('Hello Scotch');

12. Using the API
var fs = require('fs'); // Filesystem API
var http = require('http'); // http API
var crypto = require('crypto'); // Crypto API

13. One thread to rule
them all!
One thread for JavaScript
Multiple threads for I/O

14. The Event Loop
Event
Queue
Single js thread Multiple
I/O
Threads
  


15. What does the code look
like?
var fs = require('fs');
var rawData = fs.readFileSync('sotr.json');
var data = JSON.parse(rawData);
console.log(new Date());
console.log(data.message);

16. Why not just be multi-
threaded?
Each thread needs more
memory
Switching between threads
costs CPU
Avoids thread safety issues

17. Scaling single threads
The Cluster API
↗ 
⇶  → 
↘ 

18. var cluster = require('cluster');
var http = require('http');
var cpus = require('os').cpus().length;
if (cluster.isMaster) {
for (var i = 0; i < cpus; i++) {
cluster.fork();
}
cluster.on('exit', function(worker, code, signal
console.log('Process ID ' + worker.process.pid
});
} else {
http.createServer(function(req, res) {...}).list
}

19. Switching mindset
From sync to async
Lots of callbacks
Callback Hell!

20. Highway to Hell
fs.readFile('sotr.json', function(err, data) {
var info = JSON.parse(data);
db.findOne({id: info.id}, function(err, record)
fs.writeFile('sotr.dat', record.title, functio
console.log('Finish job');
})
})
})

21. Escape from Nested
Callbacks
Break it apart
Use a async module like
"async"
Promises
Generators (ES6)

22. Node as a web
application
var http = require('http');
var server = http.createServer(function(req, res)
res.end('Hello Scotch!');
});
server.listen(80);

23. Modules
// conf.js
function Conference(name, year) {
this.name = name; this.year = year;
};
Conference.prototype.getTitle = function() {
return this.name + ' ' + this.year;
};
module.exports = Conference
// index.js
var Conf = require(__dirname + '/conf.js');
var sotr = new Conf('Scotch on the Rocks', 2014);
console.log(sotr.getTitle());

24. npm
The Node.js Package Manager

25. Initialise your
project
npm init
name: (conference) sotr-example
version: (0.0.0) 0.1.2
description: An example project
entry point: (index.js) index.js
test command: grunt nodeunit
git repository: git://github.com/misterdai/isnota.
keywords: example, app
author: David Boyer
license: (BSD-2-Clause) MIT

26. Finding modules
https://npmjs.org
https://nodejsmodules.org/
http://eirikb.github.io/nipster/

27. Common modules
Databases: mysql, mongodb,
sqlite
Callbacks: async, q, when, co
Testing: Mocha, nodeunit,
should
Templating: Jade, handlebars,
ejs
Web frameworks: express,

28. Installing modules
npm install async
npm install --save coffee-script
npm install --save-dev grunt-imagemin
npm install
npm uninstall --save coffee-script

29. Installing commands
npm install -g coffee-script
npm uninstall -g grunt-cli
npm install -g gulp

30. Other npm super
powers
Publish modules
Execute scripts (e.g. npm build,
npm run)
Bump your version number
(semver)

31. Summary
Let npm manage your modules
Use it to install useful tools
such as grunt
Don't have to keep
node_modules in source
control
Store project related
commands in package.json

32. Express yourself
Express, a web framework for
Node.js
Very flexible
Minimal

33. Version 4
Bundled middleware are now
their own modules*.
* Except "static".
More robust routing.
app.router()is gone and
more flexible methods are now
available.

34. Installing
mkdir website
cd website
npm init
npm install --save express
touch index.js

35. A static site
Serving static files from a
directory

36. A dynamic site
JavaScript providing the content

37. A template engine
https://github.com/visionmedia/consoli
Jade, EJS (Embedded JavaScript),
Handlebars...

38. Try being MEAN!

Popular stack for building Node.js
based web apps.
MongoDB
E xpress
AngularJS
Node.js

39. Thanks for
listening to my
first ever
conference talk

40. Questions

If we have time...
...or catch me at the bar .

41. GAME  OVER
All aboard the
NodeJS Express
David "Mister Dai"
Boyer
 @misterdai